<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" type="text/css" href="./jquery/easyui.css">
    <link rel="stylesheet" type="text/css" href="./jquery//icon.css">
    <link rel="stylesheet" type="text/css" href="./jquery/demo.css">
    <script type="text/javascript" src="./jquery/jquery.min.js"></script>
    <script type="text/javascript" src="./jquery/jquery.easyui.min.js"></script>
    <script type="text/javascript" src="./jquery/echarts.common.min.js"></script>
</head>
<body>
<ul>
    <li>苹果</li>
    <li>香蕉</li>
    <li>橘子</li>
</ul>
</body>
<script>
    window.onload = function(){
        //定义一个快捷方式
        function $(name){
            return document.getElementsByTagName(name);
        }
        //创建一个新的节点
        var li = document.createElement("li");
        li.innerHTML="柚子";
        $('ul')[0].appendChild(li);
    }
</script>
</html>